Maximising beef and lamb daily liveweight gain during grass flush

Did you know grazed grass can be up to 50% deficient in trace elements? Sudden increase of mid-season grass growth may impact daily liveweight gains.

The recent significant early summer rain is likely to trigger a mid-grazing season grass growth increase, says independent beef and sheep grazing consultant, Liz Genever.

“Typically, 50% of the grazing season’s grass growth happens by the end of May. However, increasing temperatures following the damp period parts of the UK experienced in early June will create ideal growing conditions for grass growth to pick up again,” she says.

Soil derived trace elements can become diluted during periods of rapid grass growth, so store cattle, youngstock and finishing lambs on summer pasture could experience a reduction in daily liveweight gain if there are deficiencies in critical trace minerals like copper, selenium, iodine and cobalt – even when there is an abundance of forage.

According to Dr Elizabeth Berry, Veterinary Director with Animax, during peak grass growth, pastures can be up to 50% deficient in the four critical trace elements. Copper, selenium, iodine and cobalt are essential for many cell functions – which affects energy turnover, production, growth, fertility and the nervous system. Unless an animal has a genetic sensitivity to copper, it may need to be supplemented with all four trace elements to avoid production setbacks caused from deficiencies.

“One of the most effective ways to ensure ruminants receive optimum supplementation of these trace minerals is to give a slow release trace element bolus,” Elizabeth says. “Once a bolus enters the animal’s rumen or reticulum, trace elements begin to release. Animax’s boluses use a proven and unique leaching bolus technology that provides trace elements at a steady, continuous rate for up to six months. The release rate does not ‘spike’ or vary between animals and optimum levels are supplied. Not only does this optimise trace element supplementation for a prolonged period of time, the administration fits in with regular herd and flock management schedules.”

Trace element requirements

According to AHDB’s Trace Element Supplementation of Beef Cattle and Sheep report, livestock typically need supplementation of cobalt, selenium and iodine to receive recommended levels in the total diet (see chart). Depending on the breed of sheep, copper supplementation may also be necessary.

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In a farm trial by Animax, Lleyn and Charollais lambs born in March and April were split into two equal groups at random the following July. One group received Animax’s Tracesure® Lamb Finisher, a slow leaching bolus with 100mg of cobalt, 315mg of iodine and 50mg of selenium, and the other group received no trace element supplementation. Over a two-month grazing period on permanent pasture, lambs supplemented with the slow leaching bolus gained on average an extra 50g per day (3kg in total) more than lambs that didn’t receive supplementation.

It is especially important for livestock farmers on forage-based systems to monitor trace element levels of pastures through forage testing or blood samples, adds Liz.

“While forage is the cheapest source of feed available to beef and sheep farmers, removing creep and other supplementary feed also reduces the ability to supplement trace elements through that feeds,” Liz says. “Trace elements have a significant impact on livestock performance, so it is essential to check for deficiencies, then optimise supplementation to prevent production losses.”

Weekly grass growth and forecasts over the four regions of Great Britain can be tracked through GrassCheckGB’s website. An industry collaboration between independent organisations such as AHDB and CIEL, the project monitors weekly grass growth between 50 dairy, beef and sheep farms.

Animax offer a range of bolus products (copper optional) visit or
 contact your local representative Tracesure® is known as Allsure® in the Republic of Ireland.